Not programming and not perl :

Take revenge on your two-man office mate who frustrates your concentration all day, every day by printing out every trivial damn email, memo and circular he receives, as they arrive, for filing in triplicate, on an ancient and extremely noisy dot-matrix printer.

Method:

1. Take 3 of those long, thin party balloons and inflate them one inside the other.(Quite hard to do!)
2. Force the result into the carriage space of said printer.
3. Tape a thumb tack to the print head.
4. Wait patiently for his first email of the afternoon to arrive.
5. Watch with long and deeply anticipated glee as the printer head starts to traverse, slows, and briefly groans, before quite literally exploding. With a noise so loud that you even you start.
6. Laugh uncontrollably as your office mate half stands, does a mid-air double-take, combined shudder and dive for cover worthy of Ang Lee. (And later attribute it to a nervous side effect.)
7. Suffer several interminable seconds of remorse and regret before it becomes clear his heart hasn't stopped.
8. Spend the rest of your life in wonderment at the utterly amazing destructive effect a balloon and a pin could have upon the not insubstantially built Epsom MX-80. An effect so destructive that no trace of either balloon or pin were ever discovered.